PHP でキー名を保持する高速配列ソート方法

$arr = ['apple' => 5, 'banana' => 1, 'cherry' => 3];
ksort($arr);
print_r($arr);

Array
(
    [apple] => 5
    [banana] => 1
    [cherry] => 3
)

function cmp($a, $b)
{
    return $a <=> $b;
}

$arr = ['apple' => 5, 'banana' => 1, 'cherry' => 3];
uasort($arr, "cmp");
print_r($arr);

Array
(
    [banana] => 1
    [cherry] => 3
    [apple] => 5
)

$scores = [
    'user1' => 85,
    'user2' => 90,
    'user3' => 75,
];

// 使用 uasort() 排序数组
function cmp($a, $b)
{
    return $a[1] <=> $b[1];
}

uasort($scores, "cmp");

Array
(
    [user3] => 75
    [user1] => 85
    [user2] => 90
)